Charged particle beam apparatuses have many functions in a plurality of industrial fields, including, but not limited to, inspection of semiconductor devices during manufacturing, testing systems, imaging systems, detecting devices, and exposure systems for lithography. Thus, there is a high demand for use of charged particle beam devices for structuring and inspecting specimen within the micrometer and nanometer scale as well as a sub-nanometer scale.
Focused charged particle optical systems using a gas field ion source emitter promise a considerable decrease in probe diameter over state of the art systems, e.g., electron microscopes or liquid metal ion source devices (LMIS). In comparison to electron microscopes, charged particle optical systems using a gas field ion source emitter promise a considerable decrease in probe diameter, e.g., due to their smaller virtual source size and the short wavelengths of ions. In comparison to LMIS devices charged particle optical systems using a gas field ion source emitter promise a considerable decrease in probe diameter, e.g., due to their smaller virtual source size and the smaller energy width of the ion beam. In particular for imaging, inspection, and testing systems, wherein an image of a specimen is obtained, there is an increasing demand for higher resolutions. Accordingly, effort has been taken to bring focused ion beam optical system using gas field ion sources to practice.
In order to enable very high resolutions, a variety of system requirements for focused ion beam optical system using a gas field ion source have to be considered. Thereby, previous technology from electron microscopes and liquid metal ion source devices can, on the one hand, be applied. On the other hand, for improving focused ion beam optical systems having gas field ion sources for image generation, the differences of focused ion beams as compared to electron beams or beams of LMIS devices have to be carefully considered.